1. Field of the Invention
The present invention relates generally to an antenna, and more particularly to a complex antenna having desired operating performance.
2. Description of the Prior Art
Wireless communication devices, such as cellular phones, notebook computers, electronic appliances, and the like, are normally equipped with an antenna that serves as a medium for transmission and reception of electromagnetic signals, such as date, audio, image, and so on. The antenna can be built outside or inside of the devices. Usually, an external antenna is not easily disturbed by inner components of the electrical device and is easily adjusted by user for achieving desired operating performance. Dipole antenna is a kind of traditional external antenna. The length of a radiating element or a grounding element of a traditional dipole antenna substantially equals to ½ wavelength (λ). While, when used in long distance transmission/reception, general dipole antenna generally has weak gain and undesired operating performance.
Taiwan Patent No. 560706 disclosed a complex antenna comprising a dipole antenna, a helical antenna, and a rod antenna which connect to one another in series. The complex antenna improves the gain of the antenna and the communication distance of the antenna is fairly increased. However, the connection area between the dipole antenna and the inner conductor of the feeding line has no any additional protection. So, the connection area is not only easy to be broken but also easy to be oxidized.
Hence, in this art, a complex antenna to overcome the above-mentioned disadvantages of the prior art will be described in detail in the following embodiment.